| Fighter | Record | Last Bout |
|---|---|---|
| Rory MacDonald | 19-4-0 | 2016-06-18 |
| Rory Markham | 17-6-0 | 2010-03-27 |
| Rory Singer | 11-9-0 | 2007-06-16 |
| Rosi Sexton | 13-5-0 | 2013-10-26 |
| Ross Pearson | 20-16-0 (1 NC) | 2019-03-30 |
| Ross Pointon | 6-17-0 | 2007-01-25 |
| Rostem Akman | 6-2-0 | 2019-10-05 |
| Rousimar Palhares | 19-8-0 | 2013-10-09 |
| Roxanne Modafferi | 25-21-0 | 2022-02-12 |
| Roy Nelson | 22-14-0 | 2017-04-15 |
| Royce Alger | 3-2-0 | 1999-07-16 |
| Royce Gracie | 15-2-3 | 2006-05-27 |
| Royston Wee | 4-1-0 | 2015-05-16 |
| Ruan Potts | 11-6-0 | 2015-02-28 |
| Rudyard Moncayo | 0-3-0 | 1995-07-14 |
| Ruslan Magomedov | 14-1-0 | 2015-10-03 |
| Russell Doane | 15-8-0 | 2018-02-24 |
| Rustam Khabilov | 24-4-0 | 2019-11-09 |
| Ryan Bader | 23-5-0 | 2016-11-19 |
| Ryan Benoit | 10-8-0 | 2021-07-31 |
| Ryan Couture | 11-5-0 | 2013-08-31 |
| Ryan Hall | 9-2-0 | 2021-12-11 |
| Ryan Janes | 10-3-0 | 2017-12-01 |
| Ryan Jensen | 21-8-0 | 2011-04-30 |
| Ryan Jimmo | 19-5-0 | 2015-05-30 |
| Ryan LaFlare | 14-3-0 | 2018-10-06 |
| Ryan MacDonald | 10-2-0 | 2019-09-14 |
| Ryan Madigan | 5-3-0 | 2009-03-07 |
| Ryan McGillivray | 12-0-1 | 2011-06-04 |
| Ryan Parker | 0-1-0 | 1995-09-08 |
| Ryan Roberts | 21-12-1 (1 NC) | 2008-04-02 |
| Ryan Thomas | 20-8-0 | 2008-11-15 |
| Ryo Chonan | 22-13-0 | 2009-04-18 |
| Shane Roller | 11-7-0 | 2012-10-05 |
| Shane del Rosario | 11-2-0 | 2012-12-15 |
| Shannon Ross | 13-9-0 | 2023-12-09 |
| Stevie Ray | 23-9-0 | 2019-10-26 |
| Thomas Ramirez | 0-1-0 | 1996-02-16 |
| Tyrone Roberts | 43-12-1 | 2000-06-09 |
| Vagner Rocha | 14-4-0 | 2014-11-07 |
| Vernon Ramos Ho | 3-1-0 | 2015-11-21 |
| Victor Rodriguez | 7-4-0 | 2021-05-22 |
| Wilson Reis | 23-10-0 | 2019-04-13 |
| Yoel Romero | 13-5-0 | 2020-03-07 |
| Zygimantas Ramaska | 9-3-0 | 2024-09-07 |